Red Bull could be hit more than rivals Ferrari and McLaren by Formula One's clampdown on engine mapping and exhaust systems, the champions' technical head Adrian Newey said on Tuesday.

The governing International Automobile Federation (FIA) has told teams to adhere to a fresh interpretation of the rules from this weekend's British Grand Prix at Silverstone.

FIA race director Charlie Whiting said at last month's European Grand Prix that some teams were using illegally 'blown' diffusers and 'extremely extreme' engine maps.

The teams have been told they cannot use the engine's electronic systems to gain aerodynamic performance by keeping exhaust gases flowing constantly through the rear of the car even when drivers lift off the throttle.

"I think we will be quite heavily affected because our car was designed around the exhaust in as much as it was part of the design right from the outset," Newey said at a media picnic on the lawn of the team's factory.

"Probably with the exception of Renault and ourselves everybody else has generally speaking copied someone else's principal, mainly ours, and adapted to the car that they had preseason.

"So it might therefore be, because our car has been designed around it (the exhaust system), it's going to be more of a hit for us but it's very difficult to forecast."

Red Bull has started all eight races this season on pole position and Germany's world champion Sebastian Vettel has won six of them.

The Renault-powered team has also won for the past two seasons at Silverstone, a high-speed circuit hitherto seen as ideal for its car's characteristics.

Slightly baffled

Newey made clear that he found it hard to fathom why the goalposts had been moved halfway through the season and said it would also be hard for FIA to enforce fairly given that all the engines were slightly different with some naturally generating more exhaust thrust than others.

"I'm slightly baffled by it because it's been declared legal forever until this race," said the man who has designed title-winning cars for Williams, McLaren and Red Bull.

"The obvious parallel is when active suspension was banned at the end of '93, where there was no regulation change. Ferrari couldn't get their active to work and suddenly it was illegal for the next year.

"It's easy to fall into the Machiavellian conspiracy theories. Whether that's true or not, I don't know and I can't comment," he said when asked whether he felt the change was a deliberate effort to rein in Red Bull.

"My read of it would be that, of our main competitors, which are clearly McLaren and Ferrari, then Ferrari probably haven't got their exhaust to work that well so they are quite happy to see the back of it.

"McLaren probably don't know whether they are going to lose more or less than us. But probably on the basis that they could probably do with a wild card thrown into the pack, they are probably relieved to have something that is different."

Red Bull leads McLaren, which has British world champions Lewis Hamilton and Jenson Button, by 89 points in the constructors' standings.

Vettel is 77 clear of Button and his Australian team mate Mark Webber.

Newey said the changes had also made considerable extra work for the team at a point in the season where the focus and budget is already starting to be split between the current car and next year's.